In recent years, LEDs have been widely used as light sources of light-emitting devices. In order to obtain white light by a light-emitting device including LEDs, a method can be employed in which, for example, (i) three types of LEDs (red LED, blue LED, and green LED) are used, or (ii) a blue LED is used as a light source for a yellow fluorescent substance. It is demanded that a light-emitting device is capable of emitting white light with sufficient luminance. In view of this, a light-emitting device including a plurality of LED chips has been commercialized.
Patent Literature 1 discloses a technique to improve efficiency of extracting light from a whole device. Specifically, a plurality of LED chips 520 are provided on a base substrate 510 in such a manner that every corner of each of the plurality of LED chips faces a corner of the adjacent one of the plurality of LED chips (see FIG. 20). With the arrangement, a distance between sides of adjacent ones of the plurality of LED chips 520 can be increased without changing center positions of respective ones of the plurality of LED chips 520, as compared to a configuration in which the same number of the plurality of LED chips 520 are arranged on the base substrate 510 in a matrix manner. This makes it possible, without enlarging a size of the base substrate 510, to prevent light emitted by each of the plurality of LED chips 520 from being absorbed and confined by the adjacent LED chips 520. Accordingly, efficiency of extracting light of the whole device can be improved.
Moreover, Patent Literature 1 also discloses a technique to reduce unevenness of chromaticity by the use of a dome-shaped color converting member which is provided in such a manner that an air layer is provided between the color converting member and an optical member.